1. Field of the Invention
The present invention relates to an information management method, an information playback apparatus, and an information management apparatus for managing whether to allow playback of copyrighted content. More specifically, the present invention relates to an information management method, an information playback apparatus, and an information management apparatus with which convenience is improved in cases where content is transferred between recording media.
2. Description of the Related Art
Recently, use of digital content such as video and audio content has become common, and recorders and players that allow recording and playback of these types of digital content have also become readily available. For example, video recorders that allow broadcasting content to be written on DVDs (Digital Versatile Disks) or HDDs (Hard Disk Drives) are rapidly becoming common. Furthermore, in addition to digital broadcasting via broadcasting satellites, terrestrial digital broadcasting has recently started. In these types of digital broadcasting, HDTV (High Definition TeleVision) video images having a resolution higher than that of conventional broadcasting are provided. Video recorders that allow broadcasting content to be recorded on an optical disk or the like while maintaining the original image quality are being developed.
As it becomes readily possible to save high-quality digital content on a portable recording medium, copyright protection for digital content becomes more important. Generally, data of current video content is accompanied by copy control information (CCI) indicating whether copying is allowed. For example, by using copy control information, for data of each piece of video content, it is possible to specify no restriction of copying (copy free), permission for copying only once (copy once), prohibition of copying (copy never), or the like. In the case of the digital broadcasting mentioned above, all content is accompanied by copy control information specifying “copy once”, and video recorders usually record such content on recording medium with the copy control information changed to “copy never”.
Video content recorded on a recording medium as “copy never” is allowed to be copied to another recording medium on condition that the data on the recording medium is deleted (or invalidated). The operation of copying data to another recording medium while deleting the original data is referred to as a “move”. For example, when a user considers that certain video content received through digital broadcasting and recorded on an HDD of a video recorder is to be saved over a long period, the video content can be moved to a portable recording medium such as a DVD. This improves convenience for the user while preventing illegitimate multiple copying.
Various techniques have been proposed to facilitate handling of content in move operations. For example, in a type of data communication system, when music content on a CD (Compact Disc) is moved from a server to a memory card, information regarding pieces of music that has been moved is stored in the memory card as transfer-history management data, so that it is possible to manage the content by the same order of pieces of music when the content is returned (moved) from the memory card to the server. This is disclosed, for example, in Japanese Unexamined Patent Application Publication No. 2001-76464 (paragraph numbers [0200] to [0202] and FIG. 36).